1. Field of the Invention
This invention relates to the vehicle body structure of a vehicle having a rear portion where an accommodation concavity capable of accommodating a folding seat is provided.
2. Description of the Related Art
A vehicle of a wagon type, which has seats in a third row provided behind seats in a second row, has been put to practical use. The seats in the third row are constituted such that the seat back can be tilted toward the seat cushion and superposed thereon, whereafter this superposed combination of the seat back and the seat cushion can be pivoted rearward, turned upside down and accommodated in an accommodation concavity provided in a rear portion of the vehicle body.
FIG. 7 shows a section of an essential part of a rear portion of a vehicle body representing a conventional vehicle body structure. FIG. 8 shows a section representing a junction between a floor pan and a side member.
In a conventional vehicle body structure, as shown in FIG. 7, a floor pan 101 has an accommodation concavity 102, formed in a central portion in a vehicle width direction, for accommodating seats. Each of opposite side portions in the vehicle width direction of the accommodation concavity 102 is erected upward to form a vertical wall portion 103. An upper end portion of the vertical wall portion 103 is bent to form a horizontal portion 104. An end portion of the horizontal portion 104 is joined to a side panel 105. A side member 106 is disposed on each side in the vehicle width direction of the accommodation concavity 102 so as to extend along the longitudinal direction of the vehicle. The side member 106 has an upwardly open U-shaped section, and has right and left flange portions 107 joined to a lower surface of the horizontal portion 104 of the floor pan 101. An acoustic insulator 108 is mounted on the top of the horizontal portion 104, and a carpet 109 is laid on an upper surface of the floor pan 101. The seat is constituted such that a lower portion of a seat back 112 is pivotally attached to a rear portion of a seat cushion 111. The seat is folded, and turned upside down, whereby the seat can be accommodated in the accommodation concavity 102.
As an example of the conventional vehicle body structure having such a folding seat, there is the technique described in a patent document 1 (Japanese Patent Publication Laid-Open No. 2001-063421).
For a vehicle having seats which can be accommodated under the floor of the vehicle, there is a demand that an ample width of the seat be secured for increased marketability, such as a comfortable ride or spaciousness. In the above-described conventional vehicle body structure, however, as shown in FIGS. 7 and 8, the floor pan 101 is composed of the accommodation concavity 102, the vertical wall portions 103, and the horizontal portions 104. The right and left flange portions 107 of the side member 106 are joined to the lower surface of the horizontal portion 104 by spot welding. In the floor pan 101, therefore, a bend 110 (bending radius) is required between the vertical wall portion 103 and the horizontal portion 104, and a joining allowance A for joining of the flange portion 107 of the side member 106 is needed. The width of the accommodation concavity 102 is decreased by a width W which is the sum of the bend 110 and the joining allowance A. The decrease in the width of the accommodation concavity 102 poses the problem that ample width of the seat cannot be secured, and marketability declines.
In the “seat accommodation structure of an automobile” described in the aforementioned patent document 1, as in the case of the above-described conventional vehicle body structure, sides of a dish-shaped member are erected from its bottom to form mounting flange portions. Side frames of a tubular shape in section are joined to lower surfaces of the mounting flange portions. Thus, a bending radius is required for the dish-shaped member. As a result, the width W of the bottom of the dish-shaped member, accordingly, the width of the seat, cannot become ample.